Conventionally, there have been practical white light sources which generate white light by converting a portion of blue light emitted by a blue LED to light having a wavelength corresponding to a color within the range of green to yellow by using a wavelength converter, and mixing the blue light with the light of the color within the range of green to yellow. Various kinds of light-emitting modules utilizing such a white light source have been commercialized.
However, a lighting fixture using such a white light source is likely to have poor color rendering properties. This is because the illumination light of the white light source does not contain a sufficient amount of red light component, which leads to poor color rendering properties.
Considering the above, there has been a proposal to improve the color rendering properties by combining the white light source with a red light source and supplementing the white light with the red light component of the red light source (Japanese Unexamined Patent Application Publication No. 2012-64888, and “Sinpen Shikisai Kagaku Handobukku”, 3rd edition, edited by the Color Science Association of Japan).
However, the inventor actually manufactured a light-emitting module by combining a white light source with a red light source and lighted the light-emitting module, and found that a color deviation occurs in the illumination light under a particular lighting condition when a red LED is used as the red light source. That is, it was found that simply combining a white light source with a red LED is not enough to maintain a preferable chromaticity of the illumination light independently from the influence of lighting conditions.
The present invention is made in view of the above-described problem, and aims to provide a light-emitting module that is capable of maintaining a preferable chromaticity of the illumination light independently from the influence of lighting conditions.